Abstract

Previous studies have established that ozone-oxygen mixtures can be used to inactivate a variety of microorganisms including bacteria, fungi and viruses. Ozone is a potent reactive oxygen species (ROS) that rapidly decays into a variety of additional short half-life ROS which have been shown to cause oxidative damage to biological molecules. I hypothesize that controlled ozone exposure and the subsequent generation of additional ROS would reduce viral infectivity by lipid and/or protein peroxidation. A proprietary ozone-oxygen delivery system was used to inactivate a series of enveloped [herpes simplex virus type-1 strain McIntyre (HSV-1), vaccinia strain Elstree (VAC), vesicular stomatitis virus strain Indiana (VSV), and influenza A strain (H1N1) A/WS/33] and non-enveloped [human adenovirus type2 (Ad2)] viruses. Plaque reduction and suspension-infection viral antigen assays were used to determine inactivation kinetics. After ozonation, HSV-1 and VSV lost up to 6 log10 infectious particles in 15 min, while VAC and influenza A lost up to 5 log10 in 40 min and 30 min, respectively. In comparison, the non-enveloped Ad2 lost up to 5 log10 in 60 min. Increasing amounts of serum supplementation in the ozone treated virus suspensions slowed the rate of inactivation in both enveloped and non-enveloped viruses, suggesting the protective effect of serum against ozone. Lipid peroxidation was determined through a chromogenic assay for malondialdehyde (MDA), a byproduct of peroxidation events. MDA concentrations were inversely correlated with virus infectivity, as MDA concentrations elevated with virus exposure time to ozone. Transmission electron microscopy images of Ad2, HSV-1, VAC and VSV confirmed the drastic morphological changes that resulted from ozone treatment. The ROS-mediated attack compromised the integrity of the lipid envelopes and protein shells of the viruses. These data suggest that a wide range of viruses can be inactivated through use of an innovative ozone delivery system, thus validating my hypothesis.

Degree

College and Department

Life Sciences; Microbiology and Molecular Biology

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